The invention relates to a process and to a device for moulding frozen confectionary articles, particularly small frozen sticks.
The small, frozen confectionery sticks are manufactured on an industrial scale by means of moulding or by means of extrusion.
When extrusion is employed, the products are manufactured by cutting, into sections, a sausage shape of plastic consistency which is relatively hard at a temperature of the order of xe2x88x926xc2x0 C. to xe2x88x927xc2x0 C., extruded vertically at the exit from a freezer. Extrusion gives the products a fine, less crystallized texture than that of moulded products. The fine texture obtained by means of extrusion is largely due to the freezing conditions in a freezer and, in particular, to the freezing temperature at the exit from the freezer. That is to say that the lower the temperature the fewer large crystals are formed. This means that the faster the freezing, the smaller the ice crystals and the finer the texture. In a freezer, freezing speed is at its maximum thanks to mixing and to the continual scraping of the wall which allow accelerated freezing of the water. A drawback of this method is that the shape of the extruded products is limited.
The freezing of a liquid composition to be frozen by means of moulding through simple thermal conduction in a mould immersed in a refrigerating solution is slower and leads to the formation of considerably larger crystals. In this process, the composition to be frozen is always metered out in the liquid state into moulds with a view to guaranteeing satisfactory filling and to preventing the creation of air pockets, and its temperature is of the order of xe2x88x922xc2x0 C. to xe2x88x923xc2x0 C. The proportion of frozen water is low and most of the process of freezing the product takes place in the moulds. This explains the presence of a coarser, more crystallized texture owing to an increase in the size of the crystals.
U.S. Pat. No. 3,632,245, for example, describes an apparatus for manufacturing multi-track short frozen sticks by means of moulding, in which rows of cells are simultaneously filled with a metered quantity of liquid composition to be frozen from distribution hoppers associated with volumetric metering devices comprising cylinders constituting metering chambers in which the liquid is successively aspirated and then expelled by means of metering pistons. After this filling operation, the cells travel in a refrigerating liquid so that the articles are frozen. As the composition to be frozen is liquid, the mere drop in pressure created by the displacement of the piston in its chamber allows perfect filling of the cylinders. Thus, identical filling of the cylinders allows the simultaneous metering of an identical volume into the moulds for all the tracks.
The object of the invention is to provide moulded products of which the quality is similar to that obtained previously in the case only of extruded products.
The invention thus relates to a process for moulding frozen confectionery, in which containers passing through a solidifying environment are filled with a predetermined volume of composition by means of a volumetric metering device connected to a distribution hopper, the said metering device comprising a metering chamber which is filled with composition in the aspiration phase and a metering element which expels the predetermined volume of composition from the chamber in the metering phase, characterized in that a hard composition is metered out whilst being kept under pressure upstream of the metering element and in that the said distribution hopper, which is dept under pressure, allows a continuous supply to the metering chamber so as to fill the moulds without the formation of air pockets.
In the context of the invention, a hard composition is an ice cream which may be frozen cream, a milk ice, a water ice, which may or may not be aerated, and the term xe2x80x9cice creamxe2x80x9d used below will refer to such compositions without distinction. A hard ice cream of this type is at xe2x88x926xc2x0 C., xe2x88x927xc2x0 C. and, in practice, emerges from a freezer. Its texture is firmer than a conventional liquid composition to be frozen and it has a percentage of frozen water relative to the total water of the recipe of 50% or more, particularly 50 to 70%, depending on the composition of the mixture to be frozen. An ice cream of this type may contain inclusions such as, for example, pieces of dried or candied fruit, pieces of jelly or fondant, crunchy pieces, sauce, caramel pieces, or pieces of chocolate or biscuit.
The invention also relates to a device for moulding frozen confectionery articles by filling containers passing through a solidifying environment with a predetermined volume of composition, the said device comprising:
a distribution hopper containing the composition;
means for metering the composition which are linked to the hopper, comprising a metering chamber, a metering element, a metering nozzle and a valve communicating either with the hopper and the metering chamber during the aspiration phase or with the metering chamber and the metering nozzle during the filling phase;
characterized in that the hopper is sealed and non-deformable and in that the device comprises means for maintaining a pressure over the composition during the aspiration phase so as entirely to fill and metering chamber.
The device according to the invention may be applied to any machine for freezing frozen confectionary articles such as, for example
a machine for freezing in brine, which is rectilinear, rotary, oval or in square movement;
a freezing machine which uses a liquid, gaseous or evaporating refrigerating fluid, which coats the moulds or sprays them for reasonably long periods;
a machine in which the moulds are transported by a conveyor in a pulsed-air tunnel to effect fast freezing, it being possible for the conveyor to be rectilinear or to be wound, for example, as a simple or double helix, which is flattened or of revolution;
any machine of the above type in which the displacement of the moulds is continuous or stepwise.
The device according to the invention may be applied very simply to existing machines by converting the metering devices so as to create an overpressure in the metering hopper, for example, by closing it by means of a lid, by rendering it gas-tight and by connecting it to a source of fluid, particularly of compressed gas, for example of compressed air. This principle of metering under pressure may apply to various types of metering depends such as, for example, metering devices with a dispensing casing and with vertical or horizontal cylinders, metering devices with valves or metering devices with immersed nozzles of the bottom-up-filler and pencil-filler type.